New Crystalline Forms

ABSTRACT

A salt of the compound N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide, which is an ethanesulphonic acid salt, a sulphuric acid salt, an ethane disulphonic acid salt, a hydrochloric acid salt, a hydrobromic acid salt, a phosphoric acid salt, an acetic acid salt, a fumaric acid salt, a maleic acid salt, a tartaric acid salt, a citric acid salt, a methanesulphonic acid salt, or a p-toluenesulphonic acid salt of said compound.

FIELD OF THE INVENTION

The present invention relates to novel salts ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide,which compound has the following formula:

This compound is useful as a CB₁ receptor ligand, and may be useful intreating pain and/or other related symptoms or diseases. The inventionalso concerns pharmaceutical compositions which include the salts, aswell as processes for the manufacture of the salts. The inventionfurther concerns methods of treating medical conditions in which CB₁receptors are implicated using the salts, for example pain, anxietydisorders, cancer, multiple sclerosis, Parkinson's disease, Huntington'schorea, Alzheimer's disease, gastrointestinal disorders andcardiovascular disorders, and the use of the salts in the manufacture ofa medicament.

BACKGROUND OF THE INVENTION

In the formulation of drug compositions, it is important for the drugsubstance to be in a form in which it can be conveniently handled andprocessed. This is of importance, not only from the point of view ofobtaining a commercially-viable manufacturing process, but also from thepoint of view of subsequent manufacture of pharmaceutical formulationscomprising the active compound.

Further, in the manufacture of drug compositions, it is important that areliable, reproducible and constant plasma concentration profile of drugis provided following administration to a patient.

Chemical stability, solid state stability, and “shelf life” of theactive ingredients are also very important factors. The drug substance,and compositions containing it, should preferably be capable of beingeffectively stored over appreciable periods of time, without exhibitinga significant change in the active component's physico-chemicalcharacteristics (e.g. its chemical composition, density, hygroscopicityand solubility).

Moreover, it is also important to be able to provide drug in a formwhich is as chemically pure as possible.

The skilled person will appreciate that, typically, if a drug can bereadily obtained in a stable form, such as a stable crystalline form,advantages may be provided, in terms of ease of handling, ease ofpreparation of suitable pharmaceutical formulations, and a more reliablesolubility profile.

WO 2005/030732 discloses a generic formula the scope of whichencompassesN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide.

A process for the synthesis ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideis described in Example 14 in WO 2006/033631.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides specific salts ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide.

More specifically, the present invention relates to a salt of thecompoundN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide,which is an ethanesulphonic acid salt, a sulphuric acid salt, an ethanedisulphonic acid salt, a hydrochloric acid salt, a hydrobromic acidsalt, a phosphoric acid salt, an acetic acid salt, a fumaric acid salt,a maleic acid salt, a tartaric acid salt, a citric acid salt, amethanesulphonic acid salt, or a p-toluenesulphonic acid salt of saidcompound.

In one embodiment of the invention the salt is an ethane sulphonic acidsalt, a sulphuric acid salt, or an ethane disulphonic acid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide.

One embodiment of the invention relates to an ethane sulphonic acid saltofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamidehaving an X-ray powder diffraction pattern with specific peaks atd-values at 14.0, 7.0, 4.99, and 4.62 Å, and/or essentially as definedin Table 1 and/or essentially as defined in FIG. 1.

Another embodiment of the invention relates to a sulphuric acid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamidehaving an X-ray powder diffraction pattern with specific peaks atd-values at 11.7, 11.3, 5.8, 5.6, 5.6, and 5.4 Å, and/or essentially asdefined in Table 2 and/or essentially as defined in FIG. 2.

A further embodiment of the invention relates to an ethane disulphonicacid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamidehaving an X-ray powder diffraction pattern essentially as defined inFIG. 3.

A yet further embodiment of the invention relates to a maleic acid saltofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamidehaving an X-ray powder diffraction pattern essentially as defined inFIG. 4.

The X-ray powder diffraction spectra for typical samples of the salts ofthe present invention are shown in the Figures hereinafter. It will beunderstood that the values of the X-ray powder diffraction pattern mayvary slightly from one machine to another or from one sample to another,and so the values quoted are not to be construed as absolute.

According to a further aspect of the invention there is provided a saltof the invention in substantially crystalline form.

Although we have found that it is possible to produce salts of theinvention in forms which are greater than 80% crystalline, by“substantially crystalline” we include greater than 20%, preferablygreater than 30%, and more preferably greater than 40% (e.g. greaterthan any of 50, 60, 70, 80 or 90%) crystalline.

According to a further aspect of the invention there is also provided asalt of the invention in partially crystalline form. By “partiallycrystalline” we include 5% or between 5% and 20% crystalline.

The degree (%) of crystallinity may be determined by the skilled personusing X-ray powder diffraction (XRPD). Other techniques, such as solidstate NMR, FT-IR, Raman spectroscopy, differential scanning calorimetry(DSC) and microcalorimetry, may also be used.

The term “stability” as defined herein includes chemical stability andsolid state stability.

By “chemical stability”, we include that it may be possible to storesalts of the invention in an isolated form, or in the form of aformulation in which it is provided in admixture with pharmaceuticallyacceptable carriers, diluents or adjuvants (e.g. in an oral dosage form,such as a tablet, capsule etc.), under normal storage conditions, withan insignificant degree of chemical degradation or decomposition.

By “solid state stability”, we include that it may be possible to storesalts of the invention in an isolated solid form, or in the form of asolid formulation in which it is provided in admixture withpharmaceutically acceptable carriers, diluents or adjuvants (e.g. in anoral dosage form, such as a tablet, capsule etc.), under normal storageconditions, with an insignificant degree of solid state transformation(e.g. crystallization, recrystallization, solid state phase transition,hydration, dehydration, solvatization or desolvatization).

Examples of “normal storage conditions” include temperatures of betweenminus 80 and plus 50° C. (preferably between 0 and 40° C. and morepreferably room temperatures, such as 15 to 30° C.), pressures ofbetween 0.1 and 2 bars (preferably at atmospheric pressure), relativehumidities of between 5 and 95% (preferably 10 to 60%), and/or exposureto 460 lux of UV/visible light, for prolonged periods (i.e. greater thanor equal to six months). Under such conditions, salts of the inventionmay be found to be less than 15%, more preferably less than 10%, andespecially less than 5%, chemically degraded/decomposed, or solid statetransformed, as appropriate. The skilled person will appreciate that theabove-mentioned upper and lower limits for temperature, pressure andrelative humidity represent extremes of normal storage conditions, andthat certain combinations of these extremes will not be experiencedduring normal storage (e.g. a temperature of 50° C. and a pressure of0.1 bar).

A further aspect of the present invention comprises processes for thepreparation of the salts. The precise conditions under which the saltsare formed may be empirically determined. The salts may be obtained bycrystallization under controlled conditions.

One embodiment of the invention relates to a process for the preparationof a salt according to the present invention, which process comprisesaddition of the appropriate acid to a solution or slurry ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamidein suitable solvent or liquid.

In one embodiment of the inventive process the appropriate acid is addedtoN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamidedissolved in a solvent selected from the group: acetates, lower alkylalcohols, aliphatic and aromatic hydrocarbons, dialkyl ethers, dialkylketones, acetonitrile, chlorinated alkanes, aqueous solvents, ormixtures thereof.

In a further embodiment of the inventive process the solvent is selectedfrom the group: C₁₋₆-alkyl acetates, linear or branched C₁₋₆-alkylalcohols, C₆₋₁₂-aliphatic hydrocarbons, C₆₋₁₀-aromatic hydrocarbons,di-C₁₋₆-alkyl ethers, di-C₁₋₆-alkyl ketones, chlorinated methanes orethanes, acetonitrile, water, or mixtures thereof.

In a yet further embodiment of the inventive process the solvent isselected from the group: ethyl acetate, iso-propyl acetate, methanol,ethanol, iso-propanol, n-heptane, diethyl ether, acetone,dichloromethane, water, or mixtures thereof.

In a further embodiment of the inventive process the solvent is selectedfrom the group: ethyl acetate, methyl iso-butyl ketone, and iso-propylacetate.

In another embodiment of the inventive process the appropriate acid isadded toN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideslurried in a liquid selected from the group: acetates, lower alkylalcohols, aliphatic and aromatic hydrocarbons, dialkyl ethers, dialkylketones, acetonitrile, chlorinated alkanes, aqueous liquids, or mixturesthereof.

In a further embodiment of the inventive process the liquid is selectedfrom the group: C₁₋₆ alkyl acetates, linear or branched C₁₋₆ alkylalcohols, C₆₋₁₂ aliphatic hydrocarbons, C₆₋₁₀ aromatic hydrocarbons,di-C₁₋₆ alkyl ethers, di-C₁₋₆ alkyl ketones, chlorinated methanes orethanes, acetonitrile, water, or mixtures thereof.

In a yet further embodiment of the inventive process the liquid isselected from the group: ethyl acetate, iso-propyl acetate, methanol,ethanol, iso-propanol, n-heptane, diethyl ether, acetone,dichloromethane, water, or mixtures thereof.

In a further embodiment of the inventive process the liquid is methyltert-butyl ether.

Crystallization temperatures and crystallization times depend upon thesalt that is to be crystallized, the concentration of that salt insolution, and the solvent system which is used.

Crystallization may also be initiated and/or effected by way of standardtechniques, for example with or without seeding with crystals of theappropriate crystalline salt of the invention.

One embodiment of the invention relates to a pharmaceutical formulationincluding a salt according to the present invention in admixture with apharmaceutically acceptable adjuvant, diluent or carrier.

Another embodiment of the invention relates to a salt according to thepresent invention for use as a medicament.

A yet further embodiment of the invention relates to the use of a saltaccording to the present invention in the manufacture of a medicamentfor the therapy of pain.

One embodiment of the invention relates to the use of a salt accordingto any the present invention in the manufacture of a medicament for thetreatment of anxiety disorders.

Another embodiment of the invention relates to the use of a saltaccording to the present invention in the manufacture of a medicamentfor the treatment of cancer, multiple sclerosis, Parkinson's disease,Huntington's chorea, Alzheimer's disease, gastrointestinal disorders andcardiovascular disorders.

A further embodiment of the invention relates to the use of a saltaccording to the present invention for the manufacture of a medicamentfor the treatment of gastroesophageal reflux disease (GERD).

A yet further embodiment of the invention relates to the use of a saltaccording to the present invention for the manufacture of a medicamentfor the treatment of functional gastrointestinal disorder (FGD).

One embodiment of the invention relates to the use of a salt accordingto the present invention for the manufacture of a medicament for thetreatment of functional dyspepsia (FD).

Another embodiment of the invention relates to the use of a saltaccording to the present invention for the manufacture of a medicamentfor the treatment of irritable bowel syndrome (IBS).

A further embodiment of the invention relates to a method for thetherapy of pain in a warm-blooded animal, comprising the step ofadministering to said animal in need of such therapy a therapeuticallyeffective amount of a salt according to the present invention.

A yet further embodiment of the invention relates to a method for thetreatment of pain, whereby a pharmaceutically and pharmacologicallyeffective amount of a salt according to the present invention isadministered to a subject in need of such treatment.

One embodiment of the invention relates to a method for the treatment ofanxiety disorders, whereby a pharmaceutically and pharmacologicallyeffective amount of a salt according to the present invention isadministered to a subject in need of such treatment.

Another embodiment of the invention relates to a method for thetreatment of cancer, multiple sclerosis, Parkinson's disease,Huntington's chorea, Alzheimer's disease, gastrointestinal disorders orcardiovascular disorders, whereby a pharmaceutically andpharmacologically effective amount of a salt according to the presentinvention is administered to a subject in need of such treatment.

A further embodiment of the invention relates to a method for thetreatment of gastroesophageal reflux disease (GERD), whereby apharmaceutically and pharmacologically effective amount of a salt a saltaccording to the present invention is administered to a subject in needof such treatment.

A yet further embodiment of the invention relates to a method for thetreatment of functional gastrointestinal disorder, whereby apharmaceutically and pharmacologically effective amount of a saltaccording to the present invention is administered to a subject in needof such treatment.

One embodiment of the invention relates to a method for the treatment offunctional dyspepsia whereby a pharmaceutically and pharmacologicallyeffective amount of a salt according to the present invention isadministered to a subject in need of such treatment.

Another embodiment of the invention relates to a method for thetreatment of irritable bowel syndrome (IBS), whereby a pharmaceuticallyand pharmacologically effective amount of a salt according to thepresent invention is administered to a subject in need of suchtreatment.

Biological Evaluation

hCB₁ Receptor Binding

Human CB₁ receptor from Receptor Biology (hCB₁) are thawed at 37° C.,passed 3 times through a 25-gauge blunt-end needle, diluted in thecannabinoid binding buffer (50 mM Tris, 2.5 mM EDTA, 5 mM MgCl₂, and 0.5mg/mL BSA fatty acid free, pH 7.4) and aliquots containing theappropriate amount of protein are distributed in 96-well plates. TheIC₅₀ of the salts of the invention at hCB₁ are evaluated from 10-pointdose-response curves done with ³H-CP55,940 at 20000 to 25000 dpm perwell (0.17-0.21 nM) in a final volume of 300 μl. The total andnon-specific binding are determined in the absence and presence of 0.2μM of HU210 respectively. The plates are vortexed and incubated for 60minutes at room temperature, filtered through Unifilters GF/B (presoakedin 0.1% polyethyleneimine) S with the Tomtec or Packard harvester using3 mL of wash buffer (50 mM Tris, 5 mM MgCl₂, 0.5 mg BSA pH 7.0). Thefilters are dried for 1 hour at 55° C. The radioactivity (cpm) iscounted in a TopCount (Packard) after adding 65 μl/well of MS-20scintillation liquid.

hCB₁ GTPγS binding

Human CB₁ receptor from Receptor Biology (hCB₁) are thawed at 37° C.,passed 3 times through a 25-gauge blunt-end needle and diluted in theGTPγS binding buffer (50 mM Hepes, 20 mM NaOH, 100 mM NaCl, 1 mM EDTA, 5mM MgCl₂, pH 7.4, 0.1% BSA). The EC₅₀ and E_(max) of the compounds ofthe invention are evaluated from 10-point dose-response curves done in300 μl with the appropriate amount of membrane protein and 100000-130000dpm of GTPg³⁵S per well (0.11-0.14 nM). The basal and maximal stimulatedbinding is determined in absence and presence of 10 μM (hCB₁) Win55,212-2 respectively. The membranes are pre-incubated for 5 minuteswith 112.5 μM (hCB₁) GDP prior to distribution in plates (30 μM (hCB₁)GDP final). The plates are vortexed and incubated for 60 minutes at roomtemperature, filtered on Unifilters GF/B (presoaked in water) with theTomtec or Packard harvester using 3 ml of wash buffer (50 MM Tris, 5 mMMgCl₂, 50 mM NaCl, pH 7.0). The filters are dried for 1 hour at 55° C.The radioactivity (cpm) is counted in a TopCount (Packard) after adding65 μl/well of MS-20 scintillation liquid. Antagonist reversal studiesare done in the same way except that (a) an agonist dose-response curveis done in the presence of a constant concentration of antagonist, or(b) an antagonist dose-response curve is done in the presence of aconstant concentration of agonist.

Based on the above assays, the dissociation constant (Ki) for aparticular compound of the invention towards a particular receptor isdetermined using the following equation:

Ki=IC ₅₀/(1+[rad]/Kd),

Wherein IC₅₀ is the concentration of the compound of the invention atwhich 50% displacement has been observed; [rad] is a standard orreference radioactive ligand concentration at that moment; and Kd is thedissociation constant of the radioactive ligand towards the particularreceptor.

Using the above-mentioned assays, the Ki towards human CB₁ receptors forcertain substances of the invention are in the range of between 3 nM and195 nM. EC₅₀ for these substances are in the range of between 2.3 nM and300 nM. Emax for these substances are in the range of between 109% and144%.

Screening for Compounds Active Against TLESR (GERD)

Adult Labrador retrievers of both genders, trained to stand in a Pavlovsling, are used. Mucosa-to-skin esophagostomies are formed and the dogsare allowed to recover completely before any experiments are done.

Motility Measurement

In brief, after fasting for approximately 17 h with free supply ofwater, a multilumen sleeve/sidehole assembly (Dentsleeve, Adelaide,South Australia) is introduced through the esophagostomy to measuregastric, lower esophageal sphincter (LES) and esophageal pressures. Theassembly is perfused with water using a low-compliance manometricperfusion pump (Dentsleeve, Adelaide, South Australia). An air-perfusedtube is passed in the oral direction to measure swallows, and anantimony electrode monitored pH, 3 cm above the LES. All signals areamplified and acquired on a personal computer at 10 Hz.

When a baseline measurement free from fasting gastric/LES phase IIImotor activity has been obtained, placebo (0.9% NaCl) or test compoundis administered intravenously (i.v., 0.5 ml/kg) in a foreleg vein. Tenmin after i.v. administration, a nutrient meal (10% peptone, 5%D-glucose, 5% Intralipid, pH 3.0) is infused into the stomach throughthe central lumen of the assembly at 100 ml/min to a fmal volume of 30ml/kg. The infusion of the nutrient meal is followed by air infusion ata rate of 500 ml/min until an intragastric pressure of 10±1 mmHg isobtained. The pressure is then maintained at this level throughout theexperiment using the infusion pump for further air infusion or forventing air from the stomach. The experimental time from start ofnutrient infusion to end of air insufflation is 45 min. The procedurehas been validated as a reliable means of triggering TLESRs.

TLESRs is defined as a decrease in lower esophageal sphincter pressure(with reference to intragastric pressure) at a rate of >1 mmHg/s. Therelaxation should not be preceded by a pharyngeal signal≦2 s before itsonset in which case the relaxation is classified as swallow-induced. Thepressure difference between the LES and the stomach should be less than2 mmHg, and the duration of the complete relaxation longer than 1 s.

Screening for Compounds Active Against IBS

In this study the effect of acute administration of a compound on thevisceromotor response to isobaric colorectal distension in rats isinvestigated (Ritchie J. Pain from distension of the pelvic colon byinflating a balloon in the irritable bowel syndrome. Gut 1973; 6:105-112. Ness T J, Gebhart G F. Colorectal distension as a noxiousvisceral stimulus: physiological and pharmacological characterization ofpseudoeffective reflexes in the rat. Brain Research 1988; 450: 153-169).

Methods

Colorectal distension (CRD) is performed in all rats (Sprague Dawley)using a paradigm of 12 consecutive distensions (or pulses) at 80 mmHgfor 30 seconds each with 4.5 minute intervals (12×80 mmHg). Thevisceromotor response is determined by quantifying phasic changes in theballoon pressure, which is processed by specially designed computersoftware. The compound is dissolved in saline and administered at thedoses of 1, 3 and 10 μmol/kg. The compound is given intravenously in avolume of 1 mL/kg between the third and fourth distension.

The invention will now be illustrated by the following non-limitingExample.

FIG. 1 shows an X-ray powder diffractogram for crystalline ethanesulphonic acid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide.

FIG. 2 shows an X-ray powder diffractogram for crystalline sulphuricacid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide.

FIG. 3 shows an X-ray powder diffractogram for crystalline ethanedisulphonic acid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}-ethane-sulfonamide.

FIG. 4 shows an X-ray powder diffractogram for crystalline maleic acidsalt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide.

X-ray powder diffraction analysis (XRPD) was performed using variableslits on samples prepared according to standard methods, for examplethose described in Giacovazzo, C. et al (1995), Fundamentals ofCrystallography, Oxford University Press; Jenkins, R. and Snyder, R. L.(1996), Introduction to X-Ray Powder Diffractometry, John Wiley & Sons,New York; Bunn, C. W. (1948), Chemical Crystallography, Clarendon Press,London; or Klug, H. P. & Alexander, L. E. (1974), X-ray DiffractionProcedures, John Wiley and Sons, New York. X-ray analyses were performedusing a PANalytical X'Pert PRO MPD diffractometer.

It will be appreciated by the skilled person that crystalline forms ofcompounds of the invention may be prepared by analogy with processesdescribed herein and/or in accordance with the Examples below, and mayshow essentially the same XRPD diffraction patterns as those disclosedherein. By “essentially the same” XRPD diffraction patterns, we includethose instances when it is clear from the relevant patterns (allowingfor experimental error) that essentially the same crystalline form hasbeen formed. When provided, XRPD distance values may vary in the range±2on the last given decimal place. It will be appreciated by the skilledperson that XRPD intensities may vary when measured for essentially thesame crystalline form for a variety of reasons including, for example,preferred orientation.

Preparation ofN-{2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide

Step A:

N-(4-{[(4,4-Difluorocyclohexyl)methyl]amino}-3-nitrophenyl)acetamide

N-(4-Fluoro-3-nitrophenyl)acetamide (1.15 g, 5.84 mmol) and[(4,4-difluorocyclohexyl)methyl]amine hydrochloride (1.30 g, 7.59 mmol)were stirred in 30 mL of EtOH containing TEA (2.40 mL, 17.5 mmol) at 80°C. for 48h. The solvent was evaporated. The residue was dissolved inEtOAc and washed with aqueous 5% KHSO₄ solution, saturated aqueousNaHCO₃ solution, saturated aqueous NaCl solution and dried overanhydrous Na₂SO₄. The product was crystallized from EtOAc. The left overmother liquor was purified by silica gel flash chromatography using2:1/hexanes:acetone as eluent. Yield: 1.50 g (78%). ¹H NMR (400 MHz,CHLOROFORM-D) δ 1.33-1.47 (m, 2H), 1.66-1.77 (m, 2H), 1.77-1.86 (m, 1H),1.89-1.93 (m, 1H), 1.93-1.97 (m, 1H), 2.10-2.17 (m, 2H), 2.18 (s, 3H),3.23 (dd, J=6.74, 5.76 Hz, 2H), 6.83 (d, J=9.37 Hz, 1H), 7.15 (s, 1H),7.80 (dd, J=9.18, 2.54 Hz, 1H), 8.09 (d, J=2.54 Hz, 2H).

Step B:

N-(3-Amino-4-{[(4,4-difluorocyclohexyl)methyl]amino}phenyl)acetamide

N-(4-{[(4,4-Difluorocyclohexyl)methyl]amino}-3-nitrophenyl)acetamide(1.48 g, 4.52 mmol) was dissolved in 50 mL of EtOAc containing acatalytic amount of 10% Pd/C. The solution was shaken in a Parrhydrogenation apparatus under H₂ atmosphere (45 psi) at rt for 24 h. Thesolution was filtered through Celite and the solvent was evaporated.Yield: 1.32 g (98%). ¹H NMR (400 MHz, CHLOROFORM-D) δ 1.31-1.43 (m, 2H),1.64-1.73 (m, 2H), 1.74-1.82 (m, 1H), 1.89-1.93 (m, 1H), 1.93-1.96 (m,1H), 2.08-2.17 (m, 5H), 3.00 (d, J=6.64 Hz, 2H), 3.27-3.46 (m, 2H), 6.55(d, J=8.40 Hz, 1H), 6.70 (dd, J=8.40, 2.34 Hz, 1H), 7.01 (s, 1H), 7.13(d, J=2.34 Hz, 1H).

Step C:

N-{2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}acetamide

N-(3-Amino-4-{[(4,4-difluorocyclohexyl)methyl]amino}phenyl)acetamide(1.32 g, 4.44 mmol) was dissolved in 100 mL of DCM containing DMAP (108mg, 0.89 mmol). Trimethylacetyl chloride (0.60 mL, 4.88 mmol) was addeddropwise and the solution was stirred at rt for 2 h. The solution waswashed with saturated aqueous NaHCO₃ solution, saturated aqueous NaClsolution and dried over anhydrous Na₂SO₄. Part of the productprecipitated during the washings and was filtered. The organic phase wasevaporated and combined with the precipitate. The product was dissolvedin 30 mL of AcOH and placed in 6 sealed tubes (5 mL/tube). Each tube washeated at 150° C. in a Personal Chemistry microwaves instrument for 2.5h. The fractions were pooled and the solvent was evaporated. The productwas dissolved in EtOAc and washed with aqueous NaHCO₃ solution,saturated aqueous NaCl solution and dried over anhydrous Na₂SO₄. Theproduct was purified by silica gel flash chromatography using2:1/acetone:hexanes as eluent. Yield: 1.11 g (68%). ¹H NMR (400 MHz,METHANOL-D₄) δ 1.40-1.49 (m, 2H), 1.52 (s, 9H), 1.60-1.65 (m, 2H),1.67-1.77 (m, 1H), 1.96-2.06 (m, 3H), 2.11 (s, 3H), 2.15-2.23 (m, 1H),4.28 (d, J=7.62 Hz, 2H), 7.35-7.39 (m, 1H), 7.40-7.44 (m, 1H), 7.85 (d,J=1.76 Hz, 1H).

Step D:

2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-amine

N-{2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}acetamide(500 mg, 1.37 mmol) was dissolved in 10 mL of 1:1/EtOH:2M HCl. Thesolution was divided into two sealed tubes (5 mL/tube). Each tube washeated at 120° C. in a Personal Chemistry microwaves instrument for 1 h.The fractions were pooled and the solvent was evaporated. The residuewas diluted with 2M NaOH and extracted (3×) with EtOAc. The organicphase was washed with saturated aqueous NaCl solution and dried overanhydrous Na₂SO₄. The solvent was evaporated. Yield: 440 mg (99%). ¹HNMR (400 MHz, CHLOROFORM-D) δ 1.40-1.52 (m, 2H), 1.52-1.54 (m, 9H),1.56-1.66 (m, 4H), 1.68-1.75 (m, 2H), 2.07-2.17 (m, 3H), 4.14 (d, J=7.62Hz, 2H), 6.65 (dd, J=8.50, 2.25 Hz, 1H), 7.04-7.09 (m, 2H).

Step E:

N-{2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide

2-tert-Butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-amine(440 mg, 1.37 mmol) and DMAP (165 mg, 1.37 mmol) were dissolved in 50 mLof DCM. Ethanesulfonyl chloride (0.170 mL, 1.78 mmol) was added dropwiseand the solution was stirred at rt for 2.5 h. The solution was washedwith saturated aqueous NaHCO₃ solution, saturated aqueous NaCl solutionand dried over anhydrous Na₂SO₄. The product was purified by silica gelflash chromatography using EtOAc as eluent. The fractions wereconcentrated and the residue was dissolved in 25 mL of MeOH. TFA (0.155mL, 2.06 mmol) was added dropwise and the solution was stirred at rt for30 min. The solvent was evaporated and the product was precipitated inether affording the title compound as its corresponding TFA salt. Yield:565 mg (78%). ¹H NMR (400 MHz, METHANOL-D₄) δ 1.29 (t, J=7.42 Hz, 3H),1.48-1.60 (m, 2H), 1.64 (s, 9H), 1.66-1.72 (m, 2H), 1.73-1.82 (m, 2H),1.99-2.09 (m, 2H), 2.18-2.28 (m, 1H), 3.11 (m, 2H), 4.50 (d, J=7.62 Hz,2H), 7.38 (dd, J=9.08, 2.05 Hz, 1H), 7.72 (d, J=2.15 Hz, 1H), 7.85 (d,J=8.98 Hz, 1H); MS (ESI) (M+H)⁺ 414.0.

Preparation of Ethane Sulphonic Acid Salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideExample 1

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(131 mg) was dissolved in ethyl acetate (1.3 ml) and ethane sulphonicacid (27 μl, 95%) was added. The mixture was heated to 55° C. todissolve everything. Then, the solution was cooled down to roomtemperature and left to crystallize over night. The resulting slurry wasfiltered off and washed with ethyl acetate (0.5 ml) and dried shortly.The resulting product (150 mg) was crystallineN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideesylate corresponding to a yield of approximately 94%.

Example 2

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(240 mg) was dissolved in ethyl acetate (2.4 ml) and ethane sulphonicacid (25 μl, 95%) was added. The mixture was heated to 50° C. and aftera few minutes it started to crystallize. Then a second portion of ethanesulphonic acid (25 μl, 95%) was added. The resulting slurry was cooleddown to room temperature and left over night before it was filtered offand washed with ethyl acetate (1 ml) and dried under vacuum at 40° C.The resulting product (280 mg) was crystallineN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideesylate.

Example 3

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(1.82 g) was dissolved in ethyl acetate (18.2 ml) at 40° C. To the clearsolution, a first portion of ethane sulphonic acid (100 μl, 95%) wasadded. Crystallisation started immediately. After 20 minutes a secondportion of acid was added (100 μl,95%). The crystallisation was left for30 minutes before a third portion of ethane sulphonic acid (178 μl,95%)was added. The resulting slurry was left over night. Then, the productwas filtered off, washed three times with ethyl acetate (3×2 ml) anddried under vacuum at 40° C. yielding 2.3 g crystalline salt.

Example 4

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzinidazol-5-yl}ethanesulfonamide(101 mg) was dissolved in iso-propylacetate (1.5 ml) at 42° C. andethane sulphonic acid (20 μl, 95%) was added. Crystallisation startedimmediately. The slurry was left for three days before it was filteredoff and washed with iso-propylacetate (3×200 μl). The product was driedat 40° C. under vacuum to yield 61 mg crystallineN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideesylate salt.

Example 5

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(111 mg) was slurried in methyl tert-butyl ether (2.1 ml) at 48° C. andethane sulphonic acid (23 μl, 95%) was added. Shortly after the slurrybecame thinner and then recrystallised into a thicker slurry which wasleft over night at room temperature. The resulting crystals werefiltered off, washed with methyl tert-butyl ether (2×400 μl) and driedat 40° C. under vacuum. A total of 105 mg (yield 75%) crystallineN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideesylate was obtained.

Example 6

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzinidazol-5-yl}ethanesulfonamide(210 mg) was dissolved in methyl iso-butyl ketone (2.1 ml). A solutionwas made of ethansulphonic acid (43.7 μl) and methyl iso-butyl ketone(1.0 ml). The methyl iso-butyl ketone/ethane sulphonic acid solution wasadded in a controlled manner over three hours. Thus, initially, to thebase solution was added 2×20 μl acid solution. Then after 30 minutesthree more additions were made (3×20 μl). Approximately 20 minutes laterthree additions of 40 μl acid solution was made and after 40 minutes 400μl was added. Finally, 20 minutes later the remaining amount of acidsolution was added. The resulting slurry was left 2.5 days with stirringbefore it was filtered off and washed with methyl iso-butyl ketone(2×200 μl). The product was dried at 40° C. under vacuum yielding 227 mgcrystallineN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideesylate salt. (yield 85%)

Example 7

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(193 mg) was dissolved in iso-propyl acetate (3 ml) at 40° C. To theresulting clear solution ethane sulphonic acid (10 μl). was added.Crystallization started immediately. After 50 minutes a second portionof acid was added (10 μl). Finally, after 10 minutes more a thirdportion of acid was added (10 μl). The slurry was left 2.5 days withstirring before it was filtered off and washed with iso-propylacetate(2×200 μl). The crystals were dried at 40° C. under vacuum. A total of213 mg esylate salt was obtained which corresponds to a yield ofapproximately 87%.

The following NMR data were obtained from the ethane sulphonic acid saltofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideof Example 2.

¹HNMR (500 MHz, DMSO-d₆):14.1 (1H, br), 10.2 (1H, br, s), 8.0 (1H, d),7.7 (1H, split s), 7.4 (1H, split d), 4.5 (2H, d), 3.1 (2H, q), 2.4 (2H,q), 2.2 (1H, br t), 2.0 (2H, br t), 1.7 (4H, m), 1.6 (9H, s), 1.5 (2H,m), 1.2 (3H, t), 1.1 (3H, t)

The crystals of Example 3 were analyzed by XRPD and the results aretabulated below (Table 1) and are shown in FIG. 1.

TABLE 1 d-value Relative (Å) intensity 14.0 vs 9.6 vw 9.2 m 8.4 vw 7.8 s7.7 s 7.0 s 6.8 m 6.7 s 5.9 w 5.4 m 5.4 w 5.1 w 5.1 m 4.99 vs 4.77 m4.62 vs 4.41 s 4.33 m 4.24 s 4.18 m 4.08 m 4.03 m 3.97 w 3.88 m 3.83 m3.79 m 3.66 m 3.59 vw 3.50 w 3.44 m 3.40 m 3.31 vw 3.28 m 3.10 m 3.05 m3.02 m 2.92 w 2.87 w 2.87 w 2.80 w 2.73 w 2.71 w 2.68 vw

The relative intensities are less reliable and instead of numericalvalues, the following definitions are used:

% relative Intensity*: Definition: >80 vs (very strong) 37-80 s (strong) 9-37 m (mediium) 5-9 w (weak)  <5 vw (very weak) *the relativeintensities are derived from the diffractograms measured with variableslits.

Preparation of Sulphuric Acid Salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideExample 8

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(132 mg) was dissolved in ethyl acetate (1.2 ml) at 45° C. To thesolution concentrated sulphuric acid was added (17 μl). Crystallizationstarted immediately. The temperature was increased shortly to 55° C.then cooled down to 20° C. and left over night. The crystals werefiltered off, washed with ethyl acetate (1.0 ml), yielding 147 mgsulphate salt.

Example 9

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(139 mg) was dissolved in ethylacetate (2 ml) at room temperature. Tothe solution concentrated sulphuric acid was added (18 μl). Theresulting slurry was evaporated to dryness and slurried in a mixture ofethanol (1.05 ml) and ethyl acetate (1.35 ml). The crystals werefiltered off and dried, yielding 87 mg sulphate salt.

Example 10

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(177 mg) was dissolved in methyl iso-butyl ketone (1.8 ml). To thesolution water (77 μl) and concentrated sulphuric acid (24 μl) wasadded. Initially, some oil formation was observed. After seeding,crystallization started. The slurry was left over night. Then thecrystals were filtered off, washed with methyl iso-butyl ketone (0.5 ml)and dried at 40° C. under vacuum. A total of 182 mg crystalline sulphatesalt was isolated.

Example 11

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(104 mg) was dissolved in ethyl acetate (1.5 ml). To the solution water(40 μl) and concentrated sulphuric acid (13 μl) was added. Initially,some oil formation was observed. The solution was heated to 50° C. toinitiate crystallization. After 1 hour it was cooled down to roomtemperature. The slurry was left over night. Then the crystals werefiltered off, washed with ethyl acetate (1 ml) and dried at 40° C. undervacuum. A total of 110 mg crystalline sulphate salt was isolated.

The following NMR data were obtained from the sulphuric acid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideof Example 11:

¹HNMR (500 MHz, DMSO-d₆):14.1 (1H, br s), 10.2 (1H,s), 8.0 (1H,d), 7.7(1H, d), 7.4 (1H, dd), 4.5 (2H,d), 3.1 (2H,q),2.2 (1H,m), 2.0 (2H, m),1.7-1.8 (4H,m), 1.6 (9H,s), 1.5 (2H,m), 1.2 (3H,t)

The crystals of Example 11 were analyzed by XRPD and the results aretabulated below (Table 2) and are shown in FIG. 2.

TABLE 2 d-value Relative (Å) intensity 14.3 w 11.7 s 11.3 s 10.7 w 10.3m 8.5 m 8.2 w 7.2 m 6.9 m 5.8 s 5.6 s 5.6 s 5.4 s 4.93 m 4.84 m 4.78 m4.61 m 4.55 m 4.35 m 4.15 m 4.09 w 3.89 m 3.76 m 3.69 w 3.39 w 3.34 w3.28 w 3.21 w 3.17 w 3.10 w 3.00 w 2.92 w 2.89 w

The relative intensities are less reliable and instead of numericalvalues, the following definitions are used:

% relative Intensity*: Definition: >60 s (strong) 17-60 m (mediium) 5-17 w (weak)  <5 vw (very weak) *the relative intensities are derivedfrom the diffractograms measured with variable slits.

Preparation of Ethane Disulphonic Acid Salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideExample 12

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(21 mg) and 1,2-ethandisulphonic acid (13 mg) was dissolved in ethylacetate (200 μl) at 40° C. After a few minutes crystallization of thesalt started. The slurry was cooled down and left at room temperature.The slurry was used as seeds in the following experiment.

Example 13

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(108 mg) was dissolved in ethyl acetate (1 ml). Then, 1,2-ethanedisulphonic acid was added (49.5 mg). Crystallization startedimmediately. The solution was seeded with a small amount of slurry fromExample 11. Then, ethyl acetate was added (0.4 ml) and the slurry wasleft over night. The crystals were filtered off, washed with ethylacetate (0.4 ml) and dried at 40° C. under vacuum. A total of 123 mgcrystalline material was obtained.

The crystals of Example 13 were analyzed by XRPD and the results areshown in FIG. 3.

Preparation of Maleic Acid Salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamideExample 14

N-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamide(263 mg) was dissolved in ethyl acetate (2.5 ml) and water (60 μl). Tothe clear solution maleic acid was added (74.5 mg). The crystallizationstarted immediately and a thick slurry was obtained. The slurry was leftover night before it was filtered off, washed with ethyl acetate (2×1ml) and dried at 40° C. under vacuum. A total of 276 mg crystallinematerial was obtained.

The crystals of Example 14 were analyzed by XRPD and the results areshown in FIG. 4.

Abbreviations

br=broad (in relation to NMR)

d=doublet (in relation to NMR)

DCM=dichloromethane

DMSO=dimethylsulfoxide

dd=doublet of doublets (in relation to NMR)

Et=ethyl

h=hour(s)

HCl=hydrochloric acid

m=multiplet (in relation to NMR)

Me=methyl

min.=minute(s)

MS=mass spectroscopy

Pd/C=palladium on carbon

q=quartet (in relation to NMR)

rt=room temperature

s=singlet (in relation to NMR)

t=triplet (in relation to NMR)

UV=ultraviolet

Prefixes n-, s-, i-, t- and tert- have their usual meanings: normal,secondary, iso, and tertiary.

1-34. (canceled)
 35. A pharmaceutical composition comprising anethanesulphonic acid salt ofN-{2-tert-butyl-1-[(4,4-difluorocyclohexyl)methyl]-1H-benzimidazol-5-yl}ethanesulfonamidehaving an X-ray powder diffraction pattern with specific peaks atd-values at 14.0, 7.0, 4.99, and 4.62 Å, in admixture with apharmaceutically acceptable diluent or carrier.
 36. A pharmaceuticalcomposition according to claim 35, wherein said salt has an X-ray powderdiffraction pattern with specific peaks at d-values at 14.0, 7.0, 4.99,and 4.62 Å, and as defined in Table 1 and FIG. 1 TABLE 1 d-valueRelative (Å) intensity 14.0 vs 9.6 vw 9.2 m 8.4 vw 7.8 s 7.7 s 4.77 m4.62 vs 4.41 s 4.33 m 4.24 s 4.18 m 3.44 m 3.40 m 3.31 vw 3.28 m 3.10 m3.05 m